A system of this kind is known from DE 196 54 829 A1. Containers used for the individual paint components are in that case steel tanks.
Aqueous paints which comprise fillers, pigments, polymers and the like are subject to microbial influences, such as bacterial or fungal infestation. Decomposition, discoloration, reduction in viscosity, and development of odor are the consequences. To protect paints against microbial infestation they are therefore admixed with a preservative in the tanks. Preservatives used are various biocides, examples being isothiazolines or formaldehyde donors.
In order to get as close as possible to meeting customer wishes for a particular paint composition, metering systems are set up in home improvement stores and similar points of sale for end customers. With such systems, certain paint components which are less popular may often reside in the storage tank for months. The tanks with the individual components for aqueous emulsion paints must therefore be admixed with unusually large amounts of biocides in order to allow the microbial infestation to be durably prevented. In certain countries, such as Germany, however, only relatively low maximum concentrations of biocides in paints are permitted. In these countries, therefore, metering systems for aqueous emulsion paints cannot be set up at such points of sale. In those countries, instead, a large range of emulsion paints, dispensed into buckets, must be held ready at the points of sale in order to allow at least part of the possible color range to be covered. This results in a correspondingly complex and costly stock-keeping.
It is an object of the invention to provide a metering system for mixing an emulsion paint from individual aqueous paint components in separate containers, with which there is no risk of microbial infestation of the paint components in the individual containers, even after months, without any biocide concentration or at any rate only with a very low biocide concentration.
This object is achieved in accordance with the metering system of the invention which provides for dispensing an aqueous emulsion paint in the desired composition, in buckets, to the end customers at the point of sale.